Marine Electrical Systems USCG Q#512 (Set 18)

The motor starts when the start button in the illustration is pushed, but stops when the button is released. What is most likely the trouble? Illustration EL-0007

USCG Exam Illustration EL-0007
USCG Examination Diagram: Illustration EL-0007
Official USCG Answer & Rule Citation

Correct Answer: Option A — an open auxiliary "M" contact

When the start button is depressed, the coil energizes, but releasing it drops out the circuit if the holding seal-in circuit fails. An open auxiliary 'M' contact prevents the control circuit from maintaining power to the main coil.

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